Question

I have a bunch of Widget objects.

Now each widget has a string property called ‘foo’. And I need to be able to query for Widgets that have ‘foo’ set to ‘red’, ‘orange’, ‘green’ or any arbitrary color, and include only Widgets that have that appropriate ‘foo’ property. Also, these colors are coming from user input, so I can’t trust them. I would rather not load all the results and then filter them, but rather do this in SQL.

However… I only see ways to join clauses with “AND”, never “OR”. And “in” is garbage (‘in’ only works on numerical IDs, or a sub-queryset, which reduces to the same problem!). I tried some other things, but they didn’t seem to work.

Basically, I’m asking how to express this as a key of filterQuery below.

myNiceWidgets = Widget.objects.filter(**filterQuery).orderBy(...)

Thanks.

Answer 1

To use OR, look into django’s Q objects.

https://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects

Widget.objects.filter(Q(foo='red') | Q(foo='green'), **filterQuery)

It won’t work as a key of filterQuery as the Q object must be a positional argument.

Lookup functions can mix the use of Q objects and keyword arguments.
All arguments provided to a lookup function (be they keyword arguments
or Q objects) are “AND”ed together. However, if a Q object is
provided, it must precede the definition of any keyword arguments. For
example: